This invention relates generally to automatic pool cleaning devices for travel over submerged surfaces of a swimming pool or the like to pick up and collect accumulated debris such as leaves, twigs, sand and silt. More particularly, this invention relates to an improved pool cleaner of the so-called suction or vacuum powered type, having means for cyclic interruption of water flow to generate pulsating forces which cause the pool cleaner to advance in steps over submerged floor and side wall surfaces of a swimming pool. The suction powered pool cleaner of the present invention includes improved drive means for generating the requisite pulsating forces to drive the cleaner in a reliable manner, with reduced risk of stalling upon ingestion of large debris.
Pool cleaner devices are generally well known in the art for use in maintaining residential and commercial swimming pools in a clean and attractive condition. In this regard, swimming pools conventionally include a water filtration system including a pump for drawing or suctioning water from the pool for circulation through a filter canister having filter media therein to remove and collect water-entrained debris such as leaves and twigs as well as fine particulate including sand and silt. From the filter canister, the water is recirculated to the pool via one or more return lines. Such filtration system is normally operated for several hours on a daily basis and serves, in combination with traditional chemical treatments such as chlorination or the like, to maintain the pool water in a clean and clear sanitary state. However, the water filtration system is ineffective to filter out debris which settles onto submerged floor and side wall surfaces of the swimming pool. In the past, settled debris has typically been removed by coupling a vacuum hose to the suction side of the pool water filtration system, such as by connecting the vacuum hose to a skimmer well located near the water surface at one side of the pool, and then manually moving a vacuum head coupled to the hose over the submerged pool surfaces to vacuum settled debris directly to the filter canister where it is collected and separated from the pool water. However, manual vacuuming of a swimming pool is a labor intensive task and is thus not typically performed by the pool owner or pool cleaning service personnel on a daily basis.
Automatic pool cleaner devices have been developed over the years for cleaning submerged pool surfaces, thereby substantially eliminating the need for labor intensive manual vacuuming. Such automatic pool cleaners typically comprise a relatively compact cleaner housing or head coupled to the pool water filtration system by a hose and including water-powered means for causing the cleaner to travel about within a swimming pool to dislodge and collect settled debris. In one form, the pool cleaner is connected to the return or pressure side of the filtration system for receiving positive pressure water which powers a turbine for rotatably driving cleaner wheels, and also functions by venturi action to draw settled debris into a filter bag. See, for example, U.S. Pat. Nos. 3,882,574; 4,558,479; 4,589,986; and 4,734,954. In another form, the pool cleaner is coupled to the suction side of the filtration system, whereby water is drawn through the pool cleaner to operate a drive mechanism for transporting the cleaner within the pool while vacuuming settled debris to the filter canister of the pool filtration system. See, for example, U.S. Pat. Nos. 3,803,658; 4,023,227; 4,133,068; 4,208,752; 4,351,077; 4,642,833; 4,742,593; 4,761,848; 4,769,867; 4,807,318; 5,265,297; 5,315,728; 5,450,645; and 5,634,229.
While both positive pressure and suction powered pool cleaners have proven to be generally effective in cleaning settled debris and the like from submerged pool surfaces, various customer preferences and installation considerations have been instrumental in causing an individual customer to choose one cleaner type over the other. More specifically, by comparison, positive pressure type cleaners are generally regarded as providing better collection of large debris such as leaves in a removable filter bag, to prevent such large debris from being drawn into and potentially clogging the filter canister of the pool water filtration system. Positive pressure cleaners are also generally viewed as having superior random travel for improved overall coverage of submerged pool surfaces. Moreover, positive pressure cleaners normally exhibit better periodic back-up or reverse function to resist entrapment in a sharp corner or the like within a pool. However, such positive pressure cleaners often require a booster pump and/or installation of an additional dedicated water return line to be integrated into the filtration system, whereby the overall cost of installing a positive pressure cleaner particularly in an existing pool can be significant. By contrast, a suction side cleaner normally can be coupled by a vacuum hose directly into the existing skimmer well of a pool, for relatively simplified connection to the suction side of the filtration system in a pool that is not equipped with a pre-installed suction side cleaner flow line. Moreover, suction side cleaners are designed for operation without requiring an additional booster pump. Accordingly, suction side cleaners have tended to be somewhat less costly to install, in comparison with pressure side cleaners. However, additional collection devices such as auxiliary leaf canisters and the like are generally required to capture large debris and thereby prevent ingestion of large leaves and the like into the filter canister of the filtration system.
Most suction side cleaners currently available on the market utilize a valve member typically in the form of a diaphragm or shuttle type valve adapted for movement between open and closed positions at a cyclic rate to disrupt the suction flow in a manner creating pressure surges or pulsations of sufficient magnitude to propel the cleaner in a forward direction in a series of incremental steps. However, this valve member has been susceptible to clogging upon ingestion of debris vacuumed from a submerged pool surface. Clogging of the valve member not only results in undesirable stalling or interruption in cleaner operation, but also creates a risk of cavitation and potential failure of the filtration system pump.
There exists, therefore, a significant need for further improvements in pool cleaners of the suction powered type, particularly with respect to providing improved drive means for propelling the cleaner throughout a swimming pool, with reduced risk of clogging in response to ingested debris. Moreover, there exists a need for providing a suction powered pool cleaner designed for enhanced randomness of travel over submerged surfaces of a swimming pool. The present invention fulfills these needs and provides further related advantages.